warner



(No Model.) I 2 sheets-Sheet 1.' E. P. WARNER, MULTIPLE SWITCH BOARD SYSTEM.

No. 433,636. Patented Aug. 5, 1890.

(NofModl.) 4 2 Sheets-Sheet 2. E. P. WARNER. MULTIPLE SWITCH BOARD SYSTEM.

Patented Aug. 5, 1890.

UNITED STATES PATENT ErrcE.

ERNEST P. VARNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO TIIE WIESTERN ELECTRIC COMPANY, OF SAME PLACE.

MULTIPLE-SWITCH-BOARD SYSTEM.

SPECIFICATION forming part of Letters Patent No. 433,636, dated August 5, 1890. Application filed January 31, 1887. Serial No. 225,984. (No'model.)

To all whom, t may concern.-

Be it known that I, ERNEST P. WARNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of 3 Illinois, have invented a certain new and useful Improvement in Multiple-Switch-Board Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings,

ro forming a part of this specification.

My invention relates to metallic circuits for multiple-switchboard systems of a telephoneexchange, and its object is to reduce, as far as possible, the number of contacts and connections between the lines and the different switch-boards. By dispensing with a large number of the connections heretofore necessary I am enabled to greatly simplify the apparatus and bring the switches on the difzo ferent switchboards within a comparativelyl small space, while the connections are made with greater facility and with more certainty than heretofore.

My invention consists in providing on each z 5 of the multiple switch-boards a socket or terininal for each line, which is permanently connected with one side thereof. The limb over which the subscriber sends his signal' extends from ground at the subscribers station through the subscribers bell and generator to a key, which key on being depressed connects with the branch extending through the subscribers drop at the exchange and thence to ground.- My invention also consists in providing a ground-connection for the test-wire of the line, Whose plug is insert-ed in the socket of another line, and also a ground-connection for each of the different test-wires, whereby 4o any test-wire is grounded when the operator connects his listening-telephone with the line. My invention further consists in switching apparatus, whereby one subscriber may ring up the subscriber with whom he is connected without signaling the exchange. By wellknown switching apparatus connected with the crank ot the generator turning the gen erator in one direction may be made to direct current to the subscribers shutter at the eentral office, while turning the generator in the opposite direction will direct the current over` the other branch or limb ot` the line, so as to call up the connected subscriber without signaling the central office. Each subscriber is thus provided with a branch or limb which is connected normally from ground at his station through his bell and generator, and thence to the subscribers switch and thence to a different normallybpen terminal on each of the switch-boards at the central office. In 6o addition to these fixed terminals or connecting-sockets, a normally-open branch is provided, which terminates in a flexible cord and plug. I provide switching apparatus in this normally-open branch, so that the telephone or generator may be connected with the line as desired.

The calling-limb ot each subscriber, as before described, is normally open at: the sub- ,i scribers telephone-switch. By means ot suit- 7o able switching apparatus at the central office the different limbs may be connected with the different ends of the loop containing the operators telephone. Thus when a subscriber takes down his telephone the operator at the central oiiice on looping in his telephone will be connected in metallic circuitwith the subscriber.

Any well-known test may be provided for indicating at any given board whether a line 8o wanted is connected or in use at any other board. I have shown the testsystem described and claimed in United States Letters Patent granted C. E. Scribner, September 9, 21.381, No. 305,021.

My invention will bereadily understood by "reference to the accompanying drawings, in which t Figure l is a diagram showing two subscribers stations with their lines extending to 9o terminals upon three ditferent switchlboards at the central otlice connected with their individual annunciators and switching apparatus, whereby the calls and connections may be made. Fig. 2 is a detail view ot the ter- 95 minals of a line and its test-wire with a plug inserted. Fig. 3 is a diagram showing two telephone-lines connected together upon one of the boards, and the generator at the subscribers station arranged to automatically roo switch the generator to send current over either branch of its subscribers metallic circuit accordingly as the generator is turned in one direction or the other.

As many switch-boards d ZJ' c are provided as may be necessary to aiford room for the operators necessary to do the switching. Each telephone-circuit is provided with a separate connection on each of the boards. Thus the telephone-circuit of subscribers station Z may be traced from ground at the said subscribers station through bell CZ and the generator e to switch f, and when the switch is in position shown, thence to telephone switch g, and thence by the receiving branch 71, of the metallic circuit to a separate switch or socket on each of the boards d b c.

The connection of wire 7i. with a metallic socket is shown in Fig. 2. The line h is thus connected with a different socket Z on each of the switch-boards, and these connections are metallic circuit.

preferably permanent, the line h being soldered or otherwise securely fastened to each of the sockets t' on the different switch-boards. Thus on each of the boards is provided a normally-open terminal or socket for each subscribers telephone-line. Now going back to switch f at the subscribers station, we liud the contact point Zt in the calling branch Zof the On closing the switch upon point k the circuit of the generator e is closed through individual annunciator Z at the central ofice. Thus by depressing key f and turning generator c the shutter of annunciator Z maybe thrown down,thus signaling the central office. Instead of depressing the keyf by hand,as abOVe described, the work maybe done automatically when the generator is turned in the proper direction, as shown in Fig. 3, the incline k upon the hub of the crank acting upon p the shaft to thrust the same endwise in the wel1-known Way to operate a switch. Any other of the well-known forms of automatic devices for doing this work might be employed. The call being thus sent, the subscriber takes down his telephone, and the position of the telephone-switch being thus changed the ground at the subscribers station is taken o and the branches h and Z of the circuit are connected together through the telephone. The operator at the same time, having seen the shutter fall, loops his telephone into the line. This he does, preferably, by means of a loop-plug or wedge m,

which he inserts between the points or strips n o. The subscriber land operator are thus connected together in metallic circuit. The operator having found out what connection is desired, at once takes up plug p and first tests the line wanted by touching the point of the plug to the test-piece, and then, if the line tests free, inserts the plug in the socket of the line wanted, as shown at board a, Fig. 3. In Fig. 2 a connecting-plug is shown thus inserted in a switch. The point of the plug coming against the socket t is electrically connected therewith. The shank of the .plug comes against the tube or test-piece q, and hence a cross or connection is made between the test-wire r and the line h through the plug, when inserted, as shown in Fig. 2.

Immediately on lifting any plug p from the switch on which it normally rests the switch rises against its upper contact, which contact is connected with the test-wire r of the line with which the plug p is connected. Thus immediately on taking up theplug of any line its test-wire is provided with a groundconnection; also, 'when the operator loops in his telephone by inserting wedge m between points n o, the strip nis lifted to contact s of the test-circuit, so that the test-wire is connected to ground through the annunciator Z of thevline. It will thus be seen that whenever a line is in use it will test busy The generator t is provided at the central office, as shown. By simply depressing key u the operators telephone may be disconnected while the generator is connected to branch h.' may be received at the central office over branch Z, while the central office may call the subscriber over branch 7.1..

It will be seen that no special clearing-out annunciator is required, since the subscriber, on hanging up his telephone, may depress key f and turn in generator, thus throwing down his shutter Z. The operator seeing plug p `in use, will know that the signal means to disconnect. As shown in the drawings, key fmust bebrought into contact with point l.: while the subscriber is calling.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. A telephone-circuit consisting of two limbs or branches, one of said limbs being connected from ground at the subscribers station to a switch device and then ce normally through the telephone-switch, and thence to Thus signal from a subscriber IOO the central-oflice switch-board, where it is normally open, the other limb being connected from a normally-open point of the telephoneswitch through the subscribers telephone and thence through the subscribers annunciator to ground at the central ofiice, in combination with a loop-switch at the central oflice and the operators telephone and generator, whereby signals maybe sent outand received and the operators telephone looped in metallic circuit with the telephone of the subscriber.

2. In a multiple-switchboard system, the combination, with the normally-open switches or sockets of each of the lines, of a test-circuit, and a branch from each test-circuit to the switch or strip s upon the loop-switch of each, whereby the test-circuit of any given line is closed to ground when the operator IIO line, each test-circuit being connected with a test-piece near each` terminal of its line on the different boards, a loop-switch in each of the metallic circuits at the central office and a branch circuit from the test-circuit of each line to a contact-piece upon the loopswitch of the line, and switching apparatus whereby any two lines may be connected together on either of the boards, while at any board it may be determined whether any line wanted or called for is connected or in use at any other board.

4:. The combination, with the test-circuit 7 of a multiple-switch-board system, of contact piece or strip the loop-switch, and the loopplug, whereby the test-circuit o is connected to ground automatically when the loop-plug is inserted in the loop-switch, substantially as shown and described.

5. In a metallic-circuit telephone-line eX- tending from an open switch or terminal of the switch-board through the subscribers outlt and through an annunciator at the central othee to ground, normally-open branch connections at the central office from each limb of the circuit to different contacts or strips, a loop-switch and a loop-plug, and a telephone in the circuit of said plug, whereby on inserting the said loop-plug in the loop-switch the said telephone will be connected in metallic circuit with the subscribers outfit, while the annunciator will be out of the metallic circuit.

6. The combination, with a metallic telephone circuit, one branch being normally open at the switch -boards and the other branch connected through an annunciator to ground at the central office, of the subscribers outfit consisting of the bell and generator in a ground branch normally closed through the telephone-switch to the branch of the circuit extending to the switch-boards, which branch is open at the said switch-boards, the subscribers telephone included in the branch which includes the annunciator at the central office, said branch being normally open at the telephone-switch when the telephone is hung on the switch, whereby on removing the telephone from the switch the ground branch at the subscribers station which includes theV bell is opened, while the subscribers telephone is looped into the metallic circuit.

7. In a telephone-circuit, the telephoneswiteh permanently connectedwith branch or limb h, which is normally open at the central oiiice, in combination with branch Z, closed to ground through an annunciator at the central ofiice, a branch to ground from the telephone-switch including a generator, and a switching device whereby current from the generator may be sent over branch l through the annunciator at the central office, as described.

8. The combination, with the different branches or limbs ot' a subscribers telephone- 1ine,of a switching device at the subscribers station, said switching device being connected with the ground branch at said station containing the generator and adapted to be closed to either branch of the telephone-line, and another subscribers telephone-line united with the telephone-line ot the tirst subscriber at the central office, and electrical connections whereby current may be directed over either branch or limb oi the telephoneline, according to the position of the switching device to call up the central ofiice or a connected subscriber, as described.

9. A telephone-circuit composed of two lines or branches leading from a central ofiice to a subscribers station, one of said lines being permanently grounded at the central olitice through an annunciator and normally open at the subscribers station, the other line being normally grounded at the subscribers station and open at t-he central ofce, in combination with switching apparatus whereby the two lines may be united in metallic circuit between the subscribers station and the central office, while at the same time the ground is removed at the subscribers station.

l0. The combination, vwith the diiierent branches or limbs of a subscribers telephoneline, of a switching device at the subscribers station, said switching device being connected with the ground branch at said station, the generator included in said ground branch, contacts with the different branches of said telephone-line, with either of which contacts said switching device is adapted to be closed and anothersubscribei"s telephone-lineunited with the telephone-line of the iirst subscriber at the central ofiiee, whereby current may be directed over either branch or limb of the telephone-line according to the position of the switching device to call up the central oiiice or a connected subscriber, as described.

In witness whereof I hereunto subscribe myname this 14th day of January, A. D. 1887.

ERNEST P. WARNER. Witnesses:

GEORGE P. BARTON, WM. M. GILLER.

IOO 

